Human Tracheobronchial Basal Cells. Normal versus Remodeling/Repairing Phenotypes In Vivo and In Vitro
Year: 2013
Type: article
Abstract: Human tracheobronchial epithelial (TBE) basal cells (BCs) function as progenitors in normal tissue. However, mechanistic studies are typically performed in vitro and frequently use BCs recovered from patients who die of nonrespiratory disease. It is not known whether the cadaveric epithelium (1) is undergoing homeostatic remodeling and/or repair, or (2) yields BC clones that represent homeostatic processes identified in tissue. We sought to compare the phenotype of TBE-BCs with that of BCs cultured under optimal clone-forming conditions. TBE pathology was evaluated using quantitative histomorphometry. The cultured BC phenotype was determined by fluorescence-activated cell sorter analysis. Clone organization and cell phenotype were determined by immunostaining. The cadaveric TBE is 20% normal. In these regions, BCs are keratin (K)-5(+) and tetraspanin CD151(+), and demonstrate a low mitotic index. In contrast, 80% of the cadaveric TBE exhibits homeostatic remodeling/repair processes. In these regions, BCs are K5(+)/K14(+), and a subset expresses tissue factor (TF). Passage 1 TBE cells are BCs that are K5(+)/TF(+), and half coexpress CD151. Optimal clone formation conditions use an irradiated NIH3T3 fibroblast feeder layer (American Type Culture Collection, Frederick, MD) and serum-supplemented Epicult-B medium (Stemcell Technologies, La Jolla, CA). The TF(+)/CD151(-) BC subpopulation is the most clonogenic BC subtype, and is enriched with K14(+) cells. TF(+)/CD151(-) BCs generate clones containing BCs that are K5(+)/Trp63(+), but K14(-)/CD151(-). TF(+) cells are limited to the clone edge. In conclusion, clonogenic human TBE BCs (1) exhibit a molecular phenotype that is a composite of the normal and remodeling/reparative BC phenotypes observed in tissue, and (2) generate organoid clones that contain phenotypically distinct BC subpopulations.
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funders: National Institutes of Health, Cancer Center, University of Colorado, National Heart, Lung, and Blood Institute, NIH Office of the Director, National Cancer Institute, National Institute of Environmental Health Sciences, National Center for Research Resources, National Center for Advancing Translational Sciences
Awards: G1541882320, Wnt Regulation of Tracheobronchial Regeneration, Novel therapeutics for vesicants and toxic inhaled chemicals (U54), Cell Based Therapy for Lung Disease, G4339663659, Lung epithelial cell survival signaling in ozone in cystic fibrosis and normals, Colorado Clinical and Translational Sciences Institute, Colorado Clinical and Translational Sciences Institute, A Promitotic Stem Cell Niche: Role For Beta-Catenin and TGFbeta, Colorado Clinical and Translational Science Institute (KL2), G9000273811, University of Colorado Cancer Center Support Grant
OpenAlex ID: W1974573818